Improvement in sheet-metal tubings



S. R. WILMOT.

A Sheet-Metal Tubing.

No. 137,991, Patented April15,l873.

AM. PHOTO'LITHOGRAPHIC c0. MY.(05EORNE19 moc'ess) NITED STATES SAMUEL B. WILMOT, OF BBIDGEPORT, CONNECTICUT,

IMPROVEMENT IN SHEET-METAL TUBINGS.

Specification forming part of Letters Patent No. 137,991, dated April 15, 1873; application filed 7 March 1, 1873.

To all whom it may concern:

Be it known that I, SAMUEL RUSSELL W11 MOT, of Bridgeport, in the county of Fairfield and State of Connecticut, have invented an Improvement in Metal Tubing, of which the following is a specification Thisinvention consists in adie-drawn lockedseam metal tube or tubing, which not only has its seam compacted and compressed in every direction, but also the whole circumferential portion of its body, both inside and out, similarly and simultaneously compacted and compressed. Metal tubing of this description is not only true and smooth externally and internally, but has a steam-tight joint, unaided by solder, and, in proportion to its Weight, is vastly stronger, and will sustain a far greater pressure than ordinary locked-seam tubing. Such improved tubing may be made from a strip of brass, copper, steel, or any other suitable metal or composition of metals, substantially as described in another application for patent made by me simultaneously with this for an improvement in the manufacture of metal tubing, and in which a strip of metal of the necessary Width and thickness, according to the required diameter and stoutness of the tubing, is drawn, as distinguished from thrust, between a longitudinally tapering male former and corresponding female former, of varying curvatures in their transverse section, to gradually bend the strip into a tubular form, and such bent strip, as it is moved forward by the draft, made to pass through a closing-die and over asuitably-constructed core, which, combined, bend the edges of the strip, and cause them to hook or interlock one with another and close the seam thus produced, after which such lockedseam tubing passes, by the draft on it, through a finishing-die provided with a mandrel or core having a longitudinal groove in'it to receive the seam, and in the course of such passage has its seam compressed and compacted from all sides or in every direction toward the center of it, and the whole circumferential portion of the body of the tube, both inside and out, is equally compacted and compressed. These means maybe more or less varied, according to circumstances, and no special claim is here made to the particular kind of seam produced.

Such tube may either be plain or fluted, and have the seam either 'on the outside or inside of it.

In the accompanying drawin g, Figure 1 rep resents an outside longitudinal view of a piece of my improved metal tubing, and Fig. 2 a transverse section of the same.

What is here claimed, and desired to be so cured by Letters Patent, is-- As an improved manufacture, lock-seamed, drawn, sheet-metal tubing, with joint or seam consolidated, and metal condensed, hardened, stiffened, and smoothed, as herein described, as results from drawing through a die or dies that impinge against, compress, consolidate, and draw upon all the exposed surfaces of the joint or seam and of the tube.

S. R. WILMOT Witnesses MICHAEL RYAN, A. GREGORY. 

